Generally, pulley to pulley drive systems, as those used in elevators, automobiles, heating, cooling, and ventilation systems, refrigeration systems, etc., are used when there is a need to transmit rotary motion. Generally, these systems consist of two pulleys and a belt. When a motor is turned on it revolves a small pulley known as a driver pulley. The belt causes a larger pulley, known as a driven pulley, wheel to rotate as well. During maintenance of such systems, the pulleys are capable of rotating; thus, creating a hazard for service personnel working in and around the system. There is therefore a need for a safety device configured to prevent the pulleys from rotating during maintenance.